CYR61 promotes obesity-induced kidney injury by activating endoplasmic reticulum stress

The objective was to assess the influence of cellular communication network factor 1 (CYR61) in obesity-induced kidney damage, as well as its potential mechanisms. An obesity-induced kidney damage was established in rats using a high-fat diet (HFD), and human proximal tubule epithelial (HK-2) cells were treated with palmitic acid (PA) for an in vitro model. Biochemical analysis was performed using test kits. The influence of CYR61 on kidney damage were evaluated by HE staining, periodic acid-Schiff staining, Masson's trichrome staining and western blot. The effect of CYR61 on cell apoptosis in vitro was assessed employing flow cytometry. The influence of CYR61 on lipid accumulation in vitro was assessed by Oil red O staining. Besides, the protein and mRNA expression levels were determined via western blot, immunohistochemistry, immunofluorescence and qRT-PCR. CYR61 was upregulated in rats with HFD-induced kidney injury and PA-treated HK-2 cells. CYR61 knockdown ameliorated metabolic parameters, kidney injury, oxidative stress, apoptosis, and inflammation, while suppressing endoplasmic reticulum (ER) stress in rats with HFD-induced kidney damage. CYR61 knockdown inhibited apoptosis, inflammation, oxidative stress, lipid accumulation and ER stress in the PA-treated HK-2 cells; however, tunicamycin reversed these inhibitory effects. These findings confirmed that CYR61 knockdown could ameliorated oxidative stress and inflammation in PA-treated HK-2 cells and HFD-induced renal damage in rats by suppressing ER stress.